Eye Pharm Flashcards
Which is a PDE inhibitor that affects vision?
Viagra
Name the 2 opposing muscles (IRIS) that control the opening of the pupil AND their receptors.
1) Pupillary Dilator - ALPHA adrenergic receptor
2) Pupillary Constrictor - muscarinic (M) receptor
Name the autonomic receptor on ciliary muscle that controls accommodation and facilitates aqueous humor outflow
Muscarinic (M) receptor
Name the autonomic receptor on ciliary epithelium (ciliary body- produces aqueous humor)
BETA adrenergic receptor
What two categories of drugs can be used to induce MYDRIASIS to facilitate an ophthalmic exam?
PHENYLEPHRINE (alpha agonist) - to act on pupillary dilator
TROPICAMIDE (anti-muscarinics) - to antagonize pupillary constrictor
What class of drugs is used to generate CYCLOPLEGIA (accommodation blockade)
Anti-muscarinics
What are the two classes of drugs that can be used to reduce intraocular pressure (IOP)?
MUSCARINIC Agonists - To facilitate AH outflow
CHOLINESTERASE Inhibitors - Same effect
Name the three anti-muscarinics
1- prototype, 1- derivative
1) ATROPINE - Prototype
2) SCOPOLAMINE - Derivative
3) TROPICAMIDE
Which of the anti-muscarinics can be used as a transdermal patch for motion sickness?
SCOPOLAMINE
Describe the pharmacokinetics (Absorption of ADME) of anti-muscarinics.
Both atropine and scopolamine are absorbed from the GUT and CONJUNCTIVA -> Antagonize the ciliary muscle + pupillary constrictor
Pneumonic for symptoms of ANTIMUSCARINIC EXCESS
Dry as a bone, Blind as a bat, Mad as a hatter, Hot as hell, Red as a beet, Full as a flask
ANTI-MUSCARINIC EXCESS 1:
Dry as a Bone
Decreased sweat, lacrimal gland secretion (tears), and salivary gland secretion (salivation)
ANTI-MUSCARINIC EXCESS 2:
Blind as a Bat
Cyclopegia (Ciliary Muscle Paralysis) - Eyes are fixed to far objects -> Can NOT accommodate lens to focus on near objects
ANTI-MUSCARINIC EXCESS 3:
Mad as a hatter
Decrease in Ach = CNS Excitation
Restlessness, Irritability, Disorientation, Delirium, Hallucination
ANTI-MUSCARINIC EXCESS 3:
Hot as hell
Decreased ability to sweat
ANTI-MUSCARINIC EXCESS 4:
Red as a Beet
Decreased ability to sweat -> Cutaneous vasodilation to try to facilitate heat dispersal
ANTI-MUSCARINIC EXCESS 5:
Full as a flask
Inability to contract bladder -> Urinary retention
How does anti-muscarinic excess affect adults and children?
ADULTS: Not life-threatening
CHILDREN: Life-threatening due to hyperthermia
TREATMENT (3) : Anti-muscarinic Excess
1) Cooling blankets
2) Benzodiazapines (DIAZEPAM) - Seizure Control
3) Cholinesterase Inhibitor (PHYSOSTIGIMINE)
Why is TROPICAMIDE used as a mydriatic, cyclopegic agent in ophthalmic exams rather than ATROPINE or SCOPOLAMINE?
Tropicamide’s Duration of Effect is SHORTER (4 hrs) as opposed to atropine and scopolamine (7-10days, 3-7days). Do not have to worry about anti-muscarinic excess
What eye pathology is ATROPINE particularly useful for? Why?
AMBLYOPIA (Lazy Eye) - Longer Half-life
Induces cyclopegia in STRONGER eye so that brain is forced to use and strengthen the weaker eye
What is the ALTERNATIVE, Second line of treatment for amblyopia?
Scopolamine (Patch)
Name the two components of SECRETING and FACILITATING aqueous humor outflow.
1) Ciliary Body Epithelium (beta adrenergic receptors) - Secrete AH
2) Ciliary Muscle (M receptors) - Contraction puts tension on TRABECULAR MESHWORK -> Facilitates outflow through the canal of Schlemm
Name the two classes of drugs used to treat glaucoma.
1) BETA ADRENERGIC BLOCKERS - ANTAGONIZE AH production by ciliary epithelium
2) CHOLINESTERASE INHIBITORS - AGONIZE ciliary muscle contraction that puts tension on the trabecular meshwork -> Increase AH outflow -> Decrease IOP
What is the FIRST line of treatment for gluacoma?
LATANOPROST
What is the mechanism of action of LATANOPROST?
Prodrug for PGF2alpha
Acts on prostaglandin receptors -> Increases UVEOSCLERAL outflow of AH
What are three classes of drugs that DECREASE Aqueous humor production to combat glaucoma?
1) BETA BLOCKERS - Timolol
2) CARBONIC ANHYDRASE INHIBITORS - Brinzolamide
3) ALPHA-2 AGONISTS - Apraclonidine
What are the two classes of drugs that increase uveoscleral outflow to combat glaucoma?
1) LATANOPROST (PGF2alpha prodrug)
2) APROCLONIDINE (alpha-2 agonist)
Which two classes of drugs contract ciliary muscle fibers, thereby increasing aqueous humor outflow to combat glaucoma?
1) CHOLINERGIC AGONIST - Pilocarpine/Carbachol
2) CHOLINESTERASE INHIBITOR - Echothiophate, Physostigimine
Clarification on UVEOSCLERAL OUTFLOW
90% of aqueous humor drains through angle of the eye -> canal of schlemm -> Venous system
10% follows an unconventional pathway (UVEOSCLERAL OUTFLOW) - Fluid flows through the ciliary muscle -> Suprachoroidal space
Which class of drug is used for CLOSED ANGLE GLAUCOMA? Name the two (1 oral, 1 IV) drugs within this class.
OSMOTIC AGENT - Increases osmotic gradient between eye and circulating blood -> Increases fluid efflux
ORAL glycerol
IV mannitol
Acts within 10mins
How do topical eye drugs access the systemic circulation?
NASAL ABSORPTION - Lacrimal drainage -> Nose (highly vascular mucosal epithelium) -> Circulation
